The ability to assemble organic molecules one carbon atom at a time has been a long-held dream for chemists. Modern boronate homologations with chiral carbenoids allow for the assembly-line synthesis of long chiral alkyl chains with excellent control over individual stereocenters. Nevertheless, heteroatom rich motives present a serious synthetic challenge to this approach. Interestingly, older methods based on substrate-controlled homologations of chiral boronic esters or umpolung of a carbonyl nucleophile can offer complementary solutions. A combination of these approaches might thus extend the range of possible targets currently within grasp of a C1-based synthesis. Link to video abstract: https://www.youtube.com/watch?v=PH_HBrqQwtg .1 Introduction2 Substrate Control: Stereoselective Addition of d1-Reagents to Aldehydes­3 Stereocontrol by Chiral Auxiliary/Director: The Matteson Boronate Homologation4 Reagent Control: Moving Chiral Information to the Carbenoid5 Conclusions and Outlook